Tilted Physics: A Cosmologically Dipole-Modulated Sky

TL;DR

This paper discusses how large-scale variations in physical constants or cosmological parameters could cause observable dipole modulations in the cosmic microwave background, leading to specific correlations in the data.

Contribution

It introduces the concept of dipole-modulation of the CMB due to position-dependent variations in fundamental constants and outlines the expected observational signatures.

Findings

Dipole modulation induces correlations between adjacent multipoles.

Future data sets can test for these dipole-modulation signals.

Theoretical framework for detecting spatial variations in cosmological parameters.

Abstract

Physical constants and cosmological parameters could vary with position. On the largest scales such variations would manifest themselves as gradients across our Hubble volume, leading to dipole-modulation of the cosmic microwave anisotropies. This generically leads to a correlation between adjacent multipoles in the spherical harmonics expansion of the sky, a distinctive signal which should be searched for in future data sets.